You must play the Card Game in order to enter the sweepstakes; however, the results of the Card Game have no bearing on your eligibility for a prize. After you play the game the entry form will appear.

Entry Limit one entry and one game play per email address per calendar day

One Grand Prize: a King’s Bounty Prize Package consisting of a 50″ LCD Smart TV, a limited edition Game of Thrones XBox and $5,000 awarded in the form of a check. (ARV: $6,249). P

Instant Win Game Prizes:

Two First Prizes – a tablet (ARV: $499 per prize)
Two Second Prizes – a Game of Thrones branded XBox 360 console (ARV: $250 per prize)
Twenty-Eight Third Prizes – A $125 American Express Gift Card

Instant Win prize winners should allow 6-8 weeks after verification of eligibility for delivery of prize. Unclaimed Instant Win prizes will not be awarded.

Prize Limit: one Sweepstakes Grand Prize and one Instant Win Prize per household.

I read this in the rules. so I guess each time you play the card game you are playing the IWS. You will be notified at the conclusion of the card game if you are a winner of the instant win game. Here is what the rules say:
“After successfully submitting your Entry, the website will reveal an Official Game Message. If the Official Game Message includes the words, “YOU’RE AN INSTANT WINNER!”, you have won the prize indicated”